Illumination system for euv projection lithography

ABSTRACT

An illumination system for EUV projection lithography has a beam shaping optical unit for generating an EUV collective output beam from an EUV raw beam of a synchrotron-radiation-based light source. An output coupling optical unit serves for generating a plurality of EUV individual output beams from the EUV collective output beam. In each case a beam guiding optical unit serves for guiding the respective EUV individual output beam toward an object field in which a lithography mask is arrangable. The result is an illumination system with which EUV light of a synchrotron-radiation-based light source is guided to the greatest possible extent without losses and at the same time flexibly.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of, and claims benefit under35 USC 120 to, international application PCT/EP2014/075257, filed Nov.21, 2014, which claims benefit under 35 USC 119 of German ApplicationNo. 10 2013 223 935.1, filed Nov. 22, 2013. The entire disclosure ofinternational application PCT/EP2014/075257 and German Application No.10 2013 223 935.1 are incorporated by reference herein.

FIELD

The disclosure relates to a beam guiding optical unit for anillumination system for EUV projection lithography. The disclosurefurthermore relates to a beam shaping optical unit and a deflectionoptical unit for an illumination system for EUV projection lithography.In addition, the disclosure relates to an illumination system for EUVprojection lithography and a projection exposure apparatus for EUVlithography. Finally, the disclosure relates to a method for producing astructured component, and a structured component produced according tothis method.

BACKGROUND

A projection exposure apparatus including an illumination system isknown from US 2011/0 014 799 A1, WO 2009/121 438 A1, US 2009/0 174 876A1, U.S. Pat. No. 6,438,199 B1 and U.S. Pat. No. 6,658,084 B2. An EUVlight source is known from DE 103 58 225 B3 and U.S. Pat. No. 6,859,515B. Further component parts for EUV projection lithography are known fromUS 2003/0002022 A1, DE 10 2009 025 655 A1, U.S. Pat. No. 6,700,952 andUS 2004/0140440 A. Further references from which an EUV light source isknown are found in WO 2009/121 438 A1. EUV illumination optical unitsare furthermore known from US 2003/0043359 A1 and U.S. Pat. No.5,896,438.

SUMMARY

The disclosure seeks to provide a deflection optical unit, a beamshaping optical unit and a beam guiding optical unit for an illuminationsystem for EUV projection lithography, and an illumination system forEUV projection lithography in such a way that provision is made for EUVlight of a synchrotron-radiation-based light source to be guided to thegreatest possible extent without losses and at the same time flexibly.

The beam guiding of EUV light or EUV radiation, provided by asynchrotron-radiation-based light source, involves a specificconditioning on account of the properties of the EUV raw beam emitted bysuch a light source. This conditioning is ensured by the beam shapingoptical unit according to the disclosure, the output coupling opticalunit and the beam guiding optical unit and by the individual beamguiding component parts, namely the deflection optical unit and thefocusing assembly.

The synchrotron-radiation-based light source can be a free electronlaser (FEL), an undulator, a wiggler or an x-ray laser. Thesynchrotron-radiation-based light source can have an etendue of lessthan 0.1 mm² or an even smaller etendue. The optical units according tothe disclosure can generally operate with the emission of a light sourcehaving such a small etendue, independently of whether asynchrotron-radiation-based light source is involved.

The beam shaping optical unit provides for a preshaping of a collectiveoutput beam from the raw beam in order to prepare for subsequent outputcoupling via the output coupling optical unit in individual outputbeams. The latter are guided to the respective object field by the beamguiding optical unit. This results in the possibility of illuminating aplurality of object fields using one and the samesynchrotron-radiation-based light source, which in turn affords thepossibility of supplying a plurality of projection exposure apparatuseswhich can be used to produce micro- or nanostructured components, forexample semi-conductor chips, in particular memory chips, via one andthe same synchrotron-radiation-based light source.

Via the output coupling optical unit and the downstream beam guidingoptical unit, it is possible to ensure a variable intensity distributionfor the proportions of the radiation power in the different EUVindividual output beams. It is thereby possible to carry out anadaptation to the number of projection exposure apparatuses to besupplied and an adaptation to the light power demanded by the respectiveprojection exposure apparatus. Different desired properties which, forproducing specific structures, are made of the light power respectivelydesired therefor can then also be fulfilled by corresponding adaptationof the illumination system.

A deflection optical unit for an illumination system for EUV projectionlithography can include a plurality of deflection mirrors on which EUVradiation impinges in a common deflection incidence plane with grazingincidence, wherein at least four deflection mirrors for grazingincidence are provided which jointly have a deflection effect in thedeflection incidence plane of more than 70°, and at least one of thedeflection mirrors is embodied as a convex cylindrical mirror and/or atleast one of the deflection mirrors is embodied as a concave cylindricalmirror. Such a deflection optical unit leads to low losses of the EUVradiation deflected by the deflection optical unit.

The mirrors for grazing incidence are designed for an angle of incidenceof greater than 60°. The angle of incidence can be even greater.

At least one of the deflection mirrors for grazing incidence can beembodied as a convex cylindrical mirror. At least one of the deflectionmirrors for grazing incidence can be embodied as a concave cylindricalmirror. Embodiments of the deflection optical unit can include a greaternumber of concave cylindrical mirrors than convex cylindrical mirrors.

An EUV beam incident in the deflection optical unit in a parallelfashion, in particular an EUV individual output beam, can have adivergence of less than 1 mrad after leaving the deflection opticalunit. Such a design of the deflection optical unit makes it possible tobe able to guide the EUV beam over a great distance.

At least one of the deflection mirrors can be embodied as displaceablein a driven fashion. In the case of such a deflection optical unit, anaspect ratio contribution of the beam guiding optical unit that isgenerated by the deflection optical unit can be adapted to a predefinedvalue. By way of example, an expansion factor for the aspect ratio canbe varied between a value 4 and a value 5 or between a value 1.5 and avalue 2 in particular in a continuously variable fashion. At least oneof the deflection mirrors for grazing incidence of the deflectionoptical unit can be embodied with a radius of curvature that is variablein a driven fashion. A further adaptation of the optical effect of thedeflection optical unit to a predefined value can be achieved as aresult.

A beam shaping optical unit for an illumination system for EUVprojection lithography can include at least two groups of mirrors onwhich EUV radiation impinges with grazing incidence, wherein each mirrorgroup has a common group incidence plane, and wherein the groupincidence planes of the mirror groups differ from one another. In thecase of such a beam shaping optical unit, the group incidence planes canbe perpendicular to one another. Mirror groups of the beam shapingoptical unit can include two mirrors, three mirrors or even moremirrors. The use of more mirror groups having different group incidenceplanes makes it possible to influence the EUV radiation in twotransverse dimensions independently for generating a desired aspectratio.

The mirror groups can be designed in the manner of Galilean telescopes.

The mirrors of the beam shaping optical unit can be embodied as e.g.convex or concave cylindrical mirrors.

The mirrors for grazing incidence are designed for an angle of incidenceof greater than 60°. The angle of incidence can be even greater.

In some embodiments, all mirrors of one of the mirror groups arearranged in the beam path downstream of a first mirror of a furthermirror group and upstream of a last mirror of the further mirror group.Such an arrangement affords the possibility of providing a largedistance between those mirrors of one and the same mirror group whichhave to provide a large expansion factor, for example, for generating adesired aspect ratio.

In some embodiments, the angles of incidence of the EUV radiation on allmirrors of one of the mirror groups are of identical magnitude. Suchangles of incidence of the EUV radiation enable a transmissionoptimization for the EUV radiation upon passing through the beam shapingoptical unit.

In some embodiments, different angles of incidence of the EUV radiationon at least two mirrors of one of the mirror groups. Such angles ofincidence increase a flexibility in the design of the beam shapingoptical unit and make it possible, for example, to adapt a grazingincidence to a predefined beam diameter of the incident EUV beam suchthat a mirror size remains within predefined dimensions.

In some embodiments, projected onto the group incidence plane of themirror group with different angles of incidence, the generated EUVcollective output beam runs in the same direction as the EUV rawbeamthat is incident in the beam shaping optical unit. Such a design ofthe beam shaping optical unit makes it possible, for example, to guidehorizontally both the beam incident in the beam shaping optical unit andthe beam emerging from the beam shaping optical unit.

A divergence of the EUV collective output beam can be less than half adivergence of the EUV raw beam. A corresponding design of the beamshaping optical unit makes it possible to be able to guide the EUVcollective output beam over a large distance.

At least one mirror of the beam shaping optical unit can have adeviation of at least 5 μm from a best fit conic. At least one mirror ofthe beam shaping optical unit can be embodied as a freeform surface.Corresponding mirror designs of the beam shaping optical unit increasethe degrees of freedom for adapting an optical effect of the beamshaping optical unit to predefined values.

A beam guiding optical unit for an illumination system for EUVprojection lithography can include a focusing assembly which transfersthe respective EUV individual output beam into an intermediate focus ofthe beam guiding optical unit. Such a beam guiding optical unit makes itpossible to guide the EUV radiation through a comparatively smallpassage opening through a stop or a wall. This enables a desiredseparation between different chambers in which the EUV radiation isguided. In addition, downstream of the intermediate focus it is possibleto use assemblies of projection exposure apparatuses which arecoordinated with an intermediate focus of the EUV illumination lightwith a predefined numerical aperture.

In some embodiments, the focusing assembly includes at least twomirrors, namely: at least one ellipsoidal mirror, on the one hand; andat least one paraboloidal mirror or at least one hyperboloidal mirror,on the other hand. Such a focusing assembly can be embodied in themanner of a type I, type II or type III Wolter mirror group. The atleast two mirrors of the focusing assembly can be arranged sequentiallyin the beam path of the EUV individual output beam.

The focusing assembly can be embodied such that a structural space ofthe focusing assembly along a beam path of the EUV individual outputbeam is approximately double the magnitude of a major semiaxis of anellipsoidal mirror of the focusing assembly. The focusing assembly canbe embodied such that a structural space of the focusing assembly alonga beam path of the EUV individual output beam is approximately fiftytimes the magnitude of a diameter of the EUV individual output beam uponentering the focusing assembly. The focusing assembly can be embodiedsuch that for a ratio b/a of a minor semiaxis b of the ellipsoidalmirror and a major semiaxis a of the ellipsoidal mirror it holds truethat: 0.7NA<b/a<0.9NA, wherein NA denotes the numerical aperture at theintermediate focus of the focusing assembly.

The focusing assembly can be embodied such that it includes at least oneparaboloidal mirror, wherein for a ratio a/f of a major semiaxis a ofthe ellipsoidal mirror and a focal length f of the paraboloidal mirrorit holds true that: a/f>50.

The focusing assembly can be embodied such that a smallest deflectionangle experienced by a marginal ray of the EUV individual output beamthrough the focusing assembly is not greater than 5°.

The object is furthermore achieved via an illumination system includinga beam shaping optical unit, an output coupling optical unit and in eachcase a beam guiding optical unit. The beam shaping optical unit and/orthe output coupling optical unit and/or the beam guiding optical unitcan be embodied in particular in accordance with the precedingdescription. The advantages are evident from those described for therespective component parts.

An illumination system for EUV projection lithography can include a beamshaping optical unit for generating an EUV collective output beam froman EUV raw beam of a synchrotron-radition-based light source, and anoutput coupling optical unit for generating a plurality of EUVindividual output beams from the EUV collective output beam, and in eachcase a beam guiding optical unit for guiding the respective EUVindividual output beam toward an object field, in which a lithographymask is arrangable. Such an illumination system makes it possible toprovide a plurality of EUV individual output beams with a predefinedaspect ratio of an EUV beam diameter. The aspect ratio contributionsprovided by the beam shaping optical unit, on the one hand, and by theoutput coupling optical unit and the downstream beam guiding opticalunit, on the other hand, can also be multiplied by a desired setpointaspect ratio, for example by the aspect ratio of an object field to beilluminated. The generation of a desired aspect ratio contribution ofthe plurality of individual output beams of 1:1, proceeding from the rawbeam, is allocated firstly ly to the generation of an aspect ratiocontribution not equal to 1 via the beam shaping optical unit and, afterthe splitting of the collective output beam into the plurality ofindividual output beams, by the generation of a corresponding aspectratio contribution by the output coupling optical unit and the beamguiding optical unit. This makes possible, on the path of the EUVillumination light from the light source as far as the object field,moderate aspect ratio changes that have to be brought about by thevarious optical assemblies through which the EUV beam passes.Alternatively, with the beam shaping optical unit firstly it is alsopossible to generate a different aspect ratio contribution, for examplean aspect ratio contribution of 1:N for N EUV individual output beams. Adownstream output coupling optical unit then still has to split the EUVcollective output beam thus generated, but then does not require its ownaspect-ratio-influencing effect for predefining the EUV individualoutput beams with the aspect ratio contribution of in each case 1:1. Adifferent distribution of the aspect ratio contributions generated bythe beam shaping optical unit, on the one hand, and by the outputcoupling optical unit and the beam guiding optical unit, on the otherhand, for generating a number N of EUV individual output beams with anaspect ratio contribution of in each case 1:1 is also possible.

The advantages of a projection exposure apparatus, of a productionmethod and of a structured component disclosed herein can correspond tothose which have already been explained above.

The light source of the illumination system can be a free electron laser(FEL), an undulator, a wiggler or an x-ray laser.

The EUV collective output beam can have within a used cross section anintensity distribution that deviates from a homogeneous intensity byless than 10% at every point of the used cross section. A respective EUVindividual output beam can have a corresponding homogeneity downstreamof the deflection optical unit.

All the mirrors of the illumination system can bear highly reflectivecoatings.

The beam shaping optical unit, the deflection optical unit and thefocusing assembly are assemblies which are also to be consideredautonomously, that is to say without the further assemblies of theillumination system.

All features of the claims can also be combined with one another in adifferent combination.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the disclosure are explained in greater detailbelow with reference to the drawing. In the drawing:

FIG. 1 schematically shows a projection exposure apparatus for EUVprojection lithography;

FIG. 2 likewise schematically shows a guiding section of an EUV beampath for a system of a plurality of projection exposure apparatusesaccording to FIG. 1, proceeding from an EUV light source for generatingan EUV raw beam to downstream of an output coupling optical unit forgenerating a plurality of EUV individual output beams from an EUVcollective output beam;

FIG. 3 shows cross-section ratios of the EUV radiation in the course ofthe EUV beam path between the light source and the beam guiding in anillumination optical unit disposed upstream of an object field of theprojection exposure apparatus;

FIG. 4 shows a side view of a beam shaping optical unit for generatingthe EUV collective output beam from the EUV raw beam;

FIG. 5 shows a further side view from direction V in FIG. 4;

FIGS. 6 and 7 show highly schematically the beam shaping optical unitaccording to FIGS. 4 and 5 for clarifying deflection angles that arebrought about by mirrors of the beam shaping optical unit;

FIGS. 8 and 9 show, in an illustration similar to FIGS. 6 and 7, afurther embodiment of a beam shaping optical unit;

FIGS. 10 and 11 show, in an illustration similar to FIGS. 6 and 7, afurther embodiment of a beam shaping optical unit;

FIG. 12 shows, less schematically than in FIGS. 1 and 2, an EUV beampath between the beam shaping optical unit and a deflection optical unitas part of a beam guiding optical unit for guiding the respective EUVindividual output beam toward the object field, wherein the deflectionoptical unit is disposed downstream of the output coupling optical unitin the beam path of the EUV individual output beam;

FIG. 13 shows highly schematically, in a sectional view parallel to theincidence plane on the deflection mirrors, an embodiment of thedeflection optical unit including, in the beam path of the EUVindividual output beam, firstly two convex cylindrical mirrors, onedownstream plane mirror and three downstream concave cylindricalmirrors;

FIG. 14 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including one convexcylindrical mirror and three concave cylindrical mirrors that followsequentially in the EUV beam path;

FIG. 15 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including, arranged one afteranother sequentially in the EUV beam path, one convex cylindricalmirror, one plane mirror and two concave cylindrical mirrors;

FIG. 16 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including, arranged one afteranother sequentially in the EUV beam path, one convex cylindricalmirror, one plane mirror and three concave cylindrical mirrors;

FIG. 17 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including, arranged one afteranother sequentially in the EUV beam path, one convex cylindricalmirror, two downstream concave cylindrical mirrors, one downstream planemirror and two downstream concave cylindrical mirrors;

FIG. 18 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including, arranged one afteranother sequentially in the EUV beam path, one convex cylindricalmirror, one downstream plane mirror and four concave cylindrical mirrorsfollowing sequentially downstream;

FIG. 19 shows, in an illustration similar to FIG. 13, a furtherembodiment of the deflection optical unit including, arranged one afteranother sequentially in the EUV beam path, one convex cylindricalmirror, two plane mirrors following sequentially downstream and threeconcave cylindrical mirrors following sequentially downstream;

FIG. 20 shows an excerpt from the beam path of one of the EUV individualoutput beams between the deflection optical unit and an intermediatefocal plane for clarifying the function of a focusing assembly or inputcoupling optical unit of the beam guiding optical unit for guiding therespective EUV individual output beam to the object field;

FIG. 21 shows, in an illustration similar to FIG. 20, a furtherembodiment of the input coupling optical unit;

FIG. 22 shows an embodiment of the input coupling optical unit of theWolter I type;

FIG. 23 shows an embodiment of the input coupling optical unit of theWolter II type;

FIG. 24 shows an embodiment of the input coupling optical unit of theWolter III type;

FIG. 25 shows a further embodiment of the input coupling optical unit ofthe Wolter III type,

FIGS. 26 to 28 show different variants of a beam shaping optical unit;

FIG. 29 shows a schematic illustration of a beam expanding componentpart.

DETAILED DESCRIPTION

A projection exposure apparatus 1 for microlithography is part of asystem including a plurality of projection exposure apparatuses, ofwhich FIG. 1 illustrates one of the projection exposure apparatuses 1.The projection exposure apparatus 1 serves for producing a micro- ornanostructured electronic semiconductor component. A light or radiationsource 2 common to all the projection exposure apparatuses of the systememits EUV radiation in the wavelength range of, for example, between 2nm and 30 nm, in particular between 2 nm and 15 nm. The light source 2is embodied as a free electron laser (FEL). This involves a synchrotronradiation source or a synchrontron-radiation-based light source whichgenerates coherent radiation having very high brilliance. Publicationsthat describe such FELs are indicated in WO 2009/121 438 A1. A lightsource 2 that can be used, for example, is described in Uwe Schindler“Ein supraleitender Undulator mit elektrisch umschaltbarer Helizität”[“A superconducting undulator having electrically switchable helicity”],Karlsruhe Research Center in the Helmholtz association, scientificreports, FZKA 6997, August 2004, in US 2007/0152171 A1 and in DE 103 58225 B3.

The light source 2 has an original etendue that is less than 0.1 mm² ina raw beam. The etendue is the smallest volume of a phase space whichcontains 90% of the light energy of an emission of a light source.Definitions of etendue that correspond thereto are found in EP 1 072 957A2 and U.S. Pat. No. 6,198,793 B1, which indicate that the etendue isobtained by multiplication of the illumination data x, y and NA², wherex and y are the field dimensions sions which span an illuminatedillumination field and NA is the numerical aperture of the fieldillumination. Even smaller etendues of the light source than 0.1 mm² arepossible, for example an etendue of less than 0.01 mm².

The EUV light source 2 has an electron beam supply device for generatingan electron beam and an EUV generation device. The latter is suppliedwith the electron beam via the electron beam supply device. The EUVgeneration device is embodied as an undulator. The undulator canoptionally include undulator magnets that are adjustable bydisplacement. The undulator can include electromagnets. A wiggler canalso be provided in the case of the light source 2.

The light source 2 has an average power of 2.5 kW. The pulse frequencyof the light source 2 is 30 MHz. Each individual radiation pulse thencarries an energy of 83 μJ. Given a radiation pulse length of 100 fs,this corresponds to a radiation pulse power of 833 MW.

A repetition rate of the light source 2 can be in the kilohertz range,for example at 100 kHz, or in the relatively low megahertz range, forexample at 3 MHz, in the medium megahertz range, for example at 30 MHz,in the upper megahertz range, for example at 300 MHz, or else in thegigahertz range, for example at 1.3 GHz.

A Cartesian xyz-coordinate system is used below in order to facilitatethe illustration of positional relationships. The x-coordinate togetherwith the y-coordinate in these illustrations regularly spans a beamcross section of the EUV illumination and imaging light 3.Correspondingly, the z-direction regularly runs in the beam direction ofthe illumination and imaging light 3. The x-direction runs verticallyfor example in FIGS. 2 and 12, that is to say perpendicularly tobuilding planes in which the system of the projection exposureapparatuses 1 is accommodated. The coordinate system in FIGS. 4 to 11 isrotated with respect thereto by 90° about the z-axis.

FIG. 1 shows main components of one of the projection exposureapparatuses 1 of the system highly schematically.

The light source 2 imitates illumination and imaging light 3 in the formfirstly of an EUV raw beam 4. FIG. 3 shows highly schematically on theleft a cross section through the EUV raw beam 4 with an x/y aspect ratioof 1:1. In general, the raw beam 4 is present as a beam having aGaussian intensity profile, that is to say as a beam that is round incross section, which is indicated by a dashed boundary line 5 in FIG. 3.The EUV raw beam 4 has a very low divergence.

A beam shaping optical unit 6 (cf. FIG. 1) serves for generating an EUVcollective output beam 7 from the EUV raw beam 4. This is illustratedvery highly schematically in FIG. 1 and somewhat less highlyschematically in FIG. 2. The EUV collective output beam 7 has a very lowdivergence. FIG. 3 elucidates, in the second cross-sectionalillustration from the left, once again an aspect ratio of the EUVcollective output beam 7. The aspect ratio is predefined by the beamshaping optical unit 6 depending on a number N of the projectionexposure apparatuses 1 to be supplied by the light source 2 within thesystem. The x/y aspect ratio generated by the beam shaping optical unit6 is generally √{square root over (N)}:1, wherein a rectangular beamprofile of the illumination light 3 results, as illustrated in FIG. 3.The EUV collective output beam 7 has the shape of a homogeneouslyilluminated rectangle. The aspect ratio contribution √{square root over(N)}:1 can also be multiplied by a desired setpoint aspect ratio, forexample by the aspect ratio of an object field to be illuminated.

FIG. 2 indicates a system design where N=4, in which the light source 2therefore supplies four projection exposure apparatuses according to thetype of the projection exposure apparatus 1 according to FIG. 1, withthe illumination light 3. For N=4, the x/y aspect ratio of the EUVcollective output beam 7 is 2:1. The number N of projection exposureapparatuses 1 can also be even greater and can be up to 10, for example.

In an alternative system design, the EUV collective output beam has anx/y aspect ratio of N:1. This ratio, too, can also be multiplied by adesired setpoint aspect ratio.

An output coupling optical unit 8 (cf. FIGS. 1 and 2) serves forgenerating a plurality of, namely N, EUV individual output beams 9 ₁ to9 _(N) (i=1, . . . N) from the EUV collective output beam 7.

FIG. 1 shows the further guidance of exactly one of the EUV individualoutput beams 9, namely of the output beam 9 ₁. The other EUV individualoutput beams 9 _(i) generated by the output coupling optical unit 8,which is likewise indicated schematically in FIG. 1, are fed to otherprojection exposure apparatuses of the system.

Downstream of the output coupling optical unit 8, the illumination andimaging light 3 is guided by a beam guiding optical unit 10 (cf. FIG. 1)towards an object field 11 of the projection exposure apparatus 1, therebeing arranged in the object field a lithography mask 12 in the form ofa reticle as object to be projected. Together with the beam guidingoptical unit 10, the beam shaping optical unit 6 and the output couplingoptical unit 8 constitute an illumination system for the projectionexposure apparatus 1.

The beam guiding optical unit 10 includes, in the order of the beam pathfor the illumination light 3, that is to say for the EUV individualoutput beam 9 _(i), a deflection optical unit 13, an input couplingoptical unit in the form of a focusing assembly 14 and a downstreamillumination optical unit 15. The illumination optical unit 15 includesa field facet mirror 16 and a pupil facet mirror 17, the function ofwhich corresponds to that known from the prior art and which aretherefore merely illustrated extremely schematically and without anassociated EUV beam path in FIG. 1.

After reflection at the field facet mirror 16, the used radiation beamof the illumination light 3, the used radiation beam being divided intoEUV sub-beams assigned to individual field facets (not illustrated) ofthe field facet mirror 16, impinges on the pupil facet mirror 17. Pupilfacets (not illustrated in FIG. 1) of the pupil facet mirror 17 areround. One of the pupil facets is assigned to each sub-beam of the usedradiation beam that is reflected from one of the field facets, such thata pair of facets impinged on and including one of the field facets andone of the pupil facets in each case predefines an illumination channelor beam guiding channel for the associated sub-beam of the usedradiation beam. The channel-by-channel assignment of the pupil facets tothe field facets is effected depending on a desired illumination by theprojection exposure apparatus 1. The illumination light 3 is thereforeguided for predefining individual illumination angles along theillumination channel sequentially via pairs including a respective oneof the field facets and a respective one of the pupil facets. Fordriving respectively predefined pupil facets, the field facet mirrorsare in each case tilted individually.

Via the pupil facet mirror 17 and, if appropriate, via a downstreamtransfer optical unit consisting of, for example, three EUV mirrors (notillustrated), the field facets are imaged into the illumination orobject field 11 in a reticle or object plane 18 of a projection opticalunit 19 (likewise illustrated schematically in FIG. 1) of the projectionexposure apparatus 1.

From the individual illumination angles that are brought about via allthe illumination channels via an illumination of the field facets of thefield facet mirror 16, there results an illumination angle distributionof the illumination of the object field 11 by the illumination opticalunit 15.

In a further embodiment of the illumination optical unit 15, inparticular given a suitable position of an entrance pupil of theprojection optical unit 19, it is also possible to dispense with themirrors of the transfer optical unit upstream of the object field 11,which leads to a corresponding increase in the transmission of theprojection exposure apparatus 1 for the used radiation beam.

The reticle 12, which reflects the used radiation beam, is arranged inthe object plane 18 in the region of the object field 11. The reticle 12is carried by a reticle holder 20, which is displaceable in a mannerdriven via a reticle displacement drive 21.

The projection optical unit 19 images the object field 11 into an imagefield 22 in an image plane 23. During the projection exposure, a wafer24 is arranged in the image plane 23, the wafer bearing alight-sensitive layer which is exposed during the projection exposure bythe projection exposure apparatus 1. The wafer 24 is carried by a waferholder 25, which is in turn displaceable in a manner controlled via awafer displacement drive 26.

During the projection exposure, both the reticle 12 and the wafer 24 inFIG. 1 are scanned in a synchronized manner in the x-direction bycorresponding driving of the reticle displacement drive 21 and of thewafer displaceable drive 26. The wafer is scanned at a scan rate oftypically 600 mm/s in the x-direction during the projection exposure.

FIGS. 4 and 5 show an embodiment of the beam shaping optical unit 6. Thebeam shaping optical unit 6 according to FIGS. 4 and 5 has a total offour mirrors BS1, BS2, BS3 and BS4, which are numbered consecutively inthe order in which the illumination light 3 impinges on them. FIG. 4shows the beam shaping optical unit 6 in a view parallel to thexz-plane. FIG. 5 shows the beam shaping optical unit 6 in a plan viewparallel to the yz-plane.

The illustration of beam deflection by the mirrors BS1 to BS4 of thebeam shaping optical unit 6 in FIGS. 4 and 5 is a departure from realityin so far as the mirrors BS1 and BS4 in FIG. 4 and the mirrors BS2 andBS3 in FIG. 5 are in each case both illustrated in the plan view withthe reflection surface facing the observer. In actual fact, a reflectionsurface of the mirror BS4 in FIG. 4 and a reflection surface of themirror BS3 in FIG. 5 face away from the observer.

The illumination light 3 impinges on all of the mirrors BS1 to BS4 withgrazing incidence. Grazing incidence is present if an angle α ofincidence between a principal direction of incidence or reflection ofthe illumination light 3 and a normal N to a reflection surface sectionof the respective mirror on which the illumination light 3 impinges isgreater than 60°. The angle α of incidence can for example be greaterthan 65°, can be greater than 70° and can also be greater than 75°.

The beam shaping optical unit 6 according to FIGS. 4 and 5 has two beamshaping mirror groups 27, 28, namely firstly the beam shaping mirrorgroup 27 including the mirrors BS1 and BS4, which are also designated by27 ₁ and 27 ₂ in FIG. 4, and the beam shaping mirror group 28 includingthe mirrors BS2 and BS3, which are also designated by 28 ₁ and 28 ₂ inFIG. 5. Each mirror group 27, 28 has a common group incidence plane. Theincidence plane of the mirror group 27 is parallel to the yz-plane(plane of the drawing in FIG. 5). The group incidence plane of themirror group 28 is parallel to the xz-plane (plane of the drawing inFIG. 4). The two group incidence planes yz and xz of the mirror groups27, 28 thus differ from one another and are perpendicular to one anotherin the embodiment illustrated.

The beam shaping mirror group 27 serves for the beam shaping of the EUVcollective output beam 7 in the yz-plane. The beam shaping mirror group28 serves for the beam shaping of the EUV collective output beam 7 inthe xz-plane.

The beam shaping mirror group 27, on the one hand, and 28, on the otherhand, have in principle the effect of a Galilean cylindrical telescope.In order to achieve a reshaping of the beam profile, for example from asubstantially round raw beam 4 having a Gaussian intensity profile intoa substantially rectangular EUV collective output beam 7 having ahomogeneous intensity profile within a rectangular used cross section,at least some of the mirrors of the beam shaping mirror groups 27 and/or28 can be provided with a freeform profile, that is to say have afreeform surface as reflection surface. A freeform profile is a heightprofile which is not representable as a conic. Conic here should also beunderstood to mean a surface shape which is described by a differentconic in two orthogonal directions; one example of such a surface shapeis a cylinder. A freeform profile is not describable by such a coniceither. The deviation of the height profile of one or more mirrors ofthe beam shaping optical unit 6 can be more than 1 micrometer (μm), inparticular more than 5 micrometers and in particular more than 20micrometers.

The mirror group 28 including the mirrors BS2 and BS3 is arrangedoverall in the beam path downstream of the first mirror BS1 of thefurther mirror group 27 and upstream of the second and last mirror BS4of the further mirror group 27.

Depending on the embodiment of the beam shaping optical unit 6, theangles of incidence of the illumination light 3 can be of identicalmagnitude on all mirrors of one of the mirror groups 27, 28 or can be ofdifferent magnitudes on at least two mirrors of one of the mirror groups27, 28. In this context, angle of incidence is understood to mean theangle of incidence of a ray running centrally in the EUV raw beam 4.

The mirror BS1 is embodied as a convex cylindrical mirror, the cylinderaxis of which runs parallel to the x-axis. The mirror BS2 is embodied asa convex cylindrical mirror, the cylinder axis of which runs parallel tothe y-axis. The mirror BS3 is embodied as a concave cylindrical mirror,the cylinder axis of which runs parallel to the y-direction. The mirrorBS4 is embodied as a concave cylindrical mirror, the cylinder axis ofwhich runs parallel to the x-axis.

The mirror group 27 provides for an expansion of a beam diameter of theraw beam in the x-dimension by a factor of 2 in comparison with theexpanding effect of the mirror group 28 in the y-dimension. Furthermore,the two mirror groups 27, 28 serve for shaping the rectangularcross-sectional contour of the EUV collective output beam 7.

FIGS. 6 to 11 show further embodiments of the beam shaping optical unit6. These embodiments differ in the sequence of the deflection anglesgenerated via the various beam shaping mirrors BSi (i=1, . . . ).Therefore, in FIGS. 6 to 11, only the deflection effect of the mirrorsBSi is illustrated in each case, without the mirrors themselves beingphysically indicated.

The embodiment of the beam shaping optical unit 6 according to FIGS. 6and 7 corresponds to the embodiments according to FIGS. 4 and 5 withregard to the angles of incidence of the illumination light 3 on themirrors BS1 to BS4 and also with regard to the assignment of the mirrorsBS1 to BS4 to the mirror groups 27, 28. The angles α of incidence of theillumination light 3 at the mirrors BS1 to BS4 are identical for allthese mirrors in the case of the embodiment according to FIGS. 6 and 7.A principal beam direction of the EUV collective output beam 7 is thusidentical to the principal beam direction of the EUV raw beam 4 incidentin the beam shaping optical unit 6.

FIGS. 8 and 9 show a further embodiment of a beam shaping optical unit29 which can be used instead of the beam shaping optical unit 6according to FIGS. 4 to 7. Component parts and functions correspondingto those which have already been explained above with reference to thebeam shaping optical unit 6 bear the same reference signs in the case ofthe beam shaping optical unit 29 and will not be discussed in detailagain.

In contrast to the beam shaping optical unit 6, different angles α, β ofincidence of the EUV radiation on the mirrors BS1 to BS4 are present inthe case of the beam shaping optical unit 29. The mirrors BS1 and BS2reflect in each case with the angle α of incidence, such that the beampath of the beam shaping optical unit 29 as far as the third mirror BS3corresponds to the beam path in the beam shaping optical unit 6. At themirrors BS3 and BS4, the illumination light 3 is reflected at a smallerangle β of incidence in comparison with the angle α of incidence, butstill with grazing incidence. This has the effect that a principal beamdirection of the EUV collective output beam 7 emerging from the beamshaping optical unit 29 does not run parallel to the z-direction, butrather forms both in the xz-plane and in the yz-plane an angle differentthan zero with respect to the incidence direction running parallel tothe z-direction.

The smaller angles β of incidence at the last two mirrors BS3 and BS4 ofthe beam shaping optical unit 29 enable a structurally smallerembodiment of the last two mirrors BS3 and BS4, that is to say anembodiment having a small extended reflection surface. This is ofgreater significance for the last two mirrors BS3 and BS4 of the beamshaping optical unit 29 than for the two leading mirrors BS1 and BS2,since at the location of the last mirrors BS3 and BS4 the illuminationlight is already significantly expanded in cross section in comparisonwith the incident EUV raw beam.

FIGS. 10 and 11 show a further embodiment of a beam shaping optical unit30 that can be used instead of the beam shaping optical units 6, 29.Component parts and functions corresponding to those which have alreadybeen explained above with reference to the beam shaping optical units 6,29 bear the same reference signs in the case of the beam shaping opticalunit 30 and will not be discussed in detail again.

The beam shaping optical unit 30 has a total of five beam shapingmirrors BS1, BS2, BS3, BS4, BS5, which are once again numberedconsecutively in the order in which the illumination light 3 impinges onthem within the beam shaping optical unit 30. The mirrors BS1, BS2 andBS5 belong to the first mirror group 27 of the beam shaping optical unit30 with a yz incidence plane. The two remaining mirrors BS3 and BS4belong to the mirror group 28 with an xz incidence plane.

After reflection at the first mirror BS1, the beam path of theillumination light 3 in the beam shaping optical unit 30 corresponds tothat in the beam shaping optical unit 29, wherein the mirrors BS2 to BS5of the beam shaping optical unit 30 then have the function of themirrors BS1 to BS4 of the beam shaping optical unit 29.

The illumination light 3, that is to say the EUV raw beam 4, impinges onthe first mirror BS1 of the beam shaping optical unit 30 with highlygrazing incidence. An angle γ of incidence of the illumination light 3on the first mirror BS1 of the beam shaping optical unit 30 is thereforegreater than the angle α of incidence. The angle γ of incidence has amagnitude such that it exactly compensates for a beam directiondifference of the illumination light 3 that is manifested by theillumination light 3 between the mirrors BS1 and BS2, on the one hand,and downstream of the mirror BS5, on the other hand, in the yz-plane,such that a principal beam direction of the illumination light 3 in theyz-plane after emerging from the beam shaping optical unit 30 isparallel to the principal beam direction in the yz-plane upon enteringthe beam shaping optical unit 30, namely parallel to the z-direction.

Upstream and downstream of the beam shaping optical unit 30, theillumination light 3 runs parallel to the building ceilings of thebuilding in which the system is accommodated.

Projected onto the group incidence plane yz of the mirror group 27 ofthe beam shaping optical unit 30, in which the individual mirrors 27 ₁(BS1), 27 ₂ (BS2) and 27 ₃ (BS5) have different angles of incidence,namely γ, α and β, the EUV collective output beam 7 generated by thebeam shaping optical unit 30 runs in the same direction, namely in thez-direction, as the EUV raw beam 4 that is incident in the beam shapingoptical unit 30.

A typical cross-sectional dimension of reflection surfaces of the lastmirror BS4 and BS5 of the beam shaping optical unit 6 and 30,respectively, is 1 m to 1.5 m, wherein these mirrors typically have areflection surface that is rectangular to a first approximation, and thespecified cross-sectional dimension relates to the longer of the twoaxes. A typical cross-sectional dimension of reflection surfaces of thefirst mirror BS1 of the beam shaping optical unit is 20 mm to 100 mm.

After leaving the beam shaping optical unit 6 or 30, the rays of the EUVcollective output beam 7 run substantially parallel. The divergence ofthe EUV collective output beam 7 can be less than 10 mrad, in particularless than 1 mrad, in particular less than 100 μrad and in particularless than 10 μrad.

FIGS. 2 and 12 show examples of the output coupling optical unit 8 forgenerating the EUV individual output beams 9 from the EUV collectiveoutput beam 7. The output coupling optical unit has a plurality ofoutput coupling mirrors 31 ₁, 31 ₂, . . . , which are assigned to theEUV individual output beams 9 ₁, 9 ₂, . . . and couple out the latterfrom the EUV collective output beam 7. FIG. 2 shows an arrangement ofthe output coupling mirrors 31 in such a way that the illumination light3 is deflected during coupling out by 90° by the output coupling mirrors31. Preference is given to an embodiment in which the output couplingmirrors 31 are operated with grazing incidence of the illumination light3, as shown schematically in FIG. 12. In the embodiment according toFIG. 2, an angle α of incidence of the illumination light 3 on theoutput coupling mirrors 31 is approximately 70°, but can also be evensignificantly above that and be in the region of 85°, for example, suchthat an effective deflection of the EUV individual output beam 9 by therespective output coupling mirror 31 in comparison with the direction ofincidence of the EUV collective output beam 7 is 10°.

Each of the output coupling mirrors 31 _(i) is thermally coupled to aheat sink (not illustrated in more detail).

FIG. 2 shows an output coupling optical unit 8 having a total of fouroutput coupling mirrors 31 ₁ to 31 ₄. FIG. 12 shows a variant of theoutput coupling optical unit 8 having a total of three output couplingmirrors 31 ₁ to 31 ₃. A different number N of output coupling mirrors 31is also possible, depending on the number N of projection exposureapparatuses 1 to be supplied by the light source 2, for example N=2 orN≧4, in particular N≧8.

After the coupling out, each of the EUV individual output beams 9 has anx/y aspect ratio of 1/√{square root over (N)}:1. The secondcross-sectional illustration from the right in FIG. 3 illustrates one ofthe EUV individual output beams 9 with this aspect ratio. For the caseN=4, the x/y aspect ratio is thus 1:2. This aspect ratio contribution,too, can also be multiplied by the desired setpoint aspect ratio.

The output coupling mirrors 31 _(i) (i=1, 2, . . . ) are arranged in thebeam path of the EUV collective output beam 7 in an offset manner onebehind another in the beam direction of the EUV collective output beam 7such that the respective closest output coupling mirror 31 _(i) reflectsa marginal cross-sectional proportion of the EUV collective output beam7 and thereby couples out the cross-sectional proportion as EUVindividual output beam 9 _(i) from the remaining EUV collective outputbeam 7 flying past the output coupling mirror 31 _(i). This outputcoupling from the edge is repeated by the following output couplingmirrors 31 _(i+1), . . . , until the last still remainingcross-sectional proportion of the EUV collective output beam 7 iscoupled out.

In the cross section of the EUV collective output beam 7, a separationis carried out between the cross-sectional proportions assigned to theEUV individual output beams 9 _(i) on separating lines 32 runningparallel to the y-axis, that is to say parallel to the shorter side ofthe x/y rectangular cross section of the EUV collective output beam 7.The separation of the EUV individual output beams 9 _(i) can be carriedout in such a way that in each case the cross-sectional proportion thatis the furthest away from the next optical component part in the beampath is cut off. This facilitates the cooling of the output couplingoptical unit 8, inter alia.

The deflection optical unit 13 downstream of the output coupling opticalunit 8 in the beam path of the illumination light 3 serves firstly fordeflecting the EUV individual output beams 9 such that they each have avertical beam direction downstream of the deflection optical unit 13,and secondly for adapting the x/y aspect ratio of the EUV individualoutput beams 9 to an x/y aspect ratio of 1:1, as illustrated on the farright in FIG. 3. This aspect ratio contribution, too, can also bemultiplied by the desired setpoint aspect ratio. The above x/y aspectratios are thus aspect ratio contributions which, multiplied by asetpoint aspect ratio, for example the aspect ratio of a rectangular orarcuate object field, yield a desired actual aspect ratio. The above x/ysetpoint aspect ratios can be the aspect ratio of a first opticalelement of an illumination optical unit 15. The above x/y setpointaspect ratios can be the aspect ratio of the angles of the illuminationlight 3 at an intermediate focus 42 of an illumination optical unit 15.

For the case where a vertical beam path of the EUV individual outputbeams 9 is already present downstream of the output coupling opticalunit 8, a deflecting effect of the deflection optical unit 13 can bedispensed with and the adaptation effect with regard to the x/y aspectratio of the EUV individual output beams 9 suffices.

The EUV individual output beams 9 downstream of the deflection opticalunit 13 can pass in such a way that, if appropriate after passingthrough a focusing assembly 14, they are incident in the illuminationoptical unit 15 at an angle, wherein this angle allows an efficientfolding of the illumination optical unit. Downstream of the deflectionoptical unit 13, the EUV individual output beam 9 _(i) can pass at anangle of 0° to 10° with respect to the perpendicular, at an angle of 10°to 20° with respect to the perpendicular, or at an angle of 20° to 30°with respect to the perpendicular.

Various variants for the deflection optical unit 13 are described belowwith reference to FIGS. 13 to 19. In this case, the illumination light 3is illustrated schematically as a single ray, that is to say that a beamillustration is dispensed with.

The divergence of the EUV individual output beam 9 _(i), after passingthrough the deflection optical unit is less than 10 mrad, in particularless than 1 mrad and in particular less than 100 μrad, that is to saythat the angle between two arbitrary rays in the beam of the EUVindividual output beam 9 _(i) is less than 20 mrad, in particular lessthan 2 mrad and in particular less than 200 μrad. This is fulfilled forthe variants described below.

The deflection optical unit 13 according to FIG. 13 deflects thecoupled-out EUV individual output beam 9 overall by a deflection angleof approximately 75°. The EUV individual output beam 9 is thus incidenton the deflection optical unit 13 according to FIG. 13 at an angle ofapproximately 15° with respect to the horizontal (xy-plane) and leavesthe deflection optical unit 13 with a beam direction parallel to thex-axis in FIG. 13. The deflection optical unit 13 has a totaltransmission for the EUV individual output beam 9 of approximately 55%.

The deflection optical unit 13 according to FIG. 13 has a total of sixdeflection mirrors D1, D2, D3, D4, D5 and D6, which are numberedconsecutively in the order in which the illumination light 3 impinges onthem in the beam path. From the deflection mirrors D1 to D6, in eachcase only a section through the reflection surface thereof isillustrated schematically, wherein a curvature of the respectivereflection surface is illustrated in a greatly exaggerated manner. Theillumination light 3 impinges on all the mirrors D1 to D6 of thedeflection optical unit 13 according to FIG. 13 with grazing incidencein a common deflection incidence plane parallel to the xz plane.

The mirrors D1 and D2 are embodied as convex cylindrical mirrors havinga cylinder axis parallel to the y-axis. The mirror D3 is embodied as aplane mirror. The mirrors D4 to D6 are embodied as concave cylindricalmirrors once again with a cylinder axis parallel to the y-axis.

The convex cylindrical mirrors are also referred to as domed mirrors.The concave cylindrical mirrors are also referred to as dished mirrors.

The combined beam shaping effect of the mirrors D1 to D6 is such thatthe x/y aspect ratio is adapted from the value 1/√{square root over(N)}:1 to the value 1:1. In the x-dimension, therefore, in the ratio thebeam cross section is stretched by the factor √{square root over (N)}.

At least one of the deflection mirrors D1 to D6 or else all of thedeflection mirrors D1 to D6 can be embodied as displaceable in thex-direction and/or in the z-direction via assigned actuators 34. Anadaptation firstly of the deflecting effect and secondly of the aspectratio adapting effect of the deflection optical unit 13 can be broughtabout as a result.

Alternatively or additionally, at least one of the deflection mirrors D1to D6 can be embodied as a mirror that is adaptable with regard to itsradius of curvature. For this purpose, the respective mirror D1 to D6can be constructed from a plurality of individual mirrors that aredisplaceable with respect to one another by an actuator system, which isnot illustrated in the drawing.

The various optical assemblies of the system including the projectionexposure apparatuses 1 can be embodied adaptively. It is thus possibleto predefine centrally how many of the projection exposure apparatuses 1are intended to be supplied with EUV individual output beams 9 _(i) fromthe light source 2 with what energetic ratio and what beam geometry isintended to be present for a respective EUV individual output beam 9after passing through the respective deflection optical unit 13.Depending on the predefined values, the EUV individual output beams 9_(i) can differ in their intensity and also in their setpoint x/y aspectratio. In particular, it is possible, by adaptively setting the outputcoupling mirrors 31 _(i), to vary the energetic ratios of the EUVindividual output beams 9 _(i) and, by adaptively setting the deflectionoptical unit 13, to keep unchanged the size and the aspect ratio of theEUV individual output beam 9 _(i) after passing through the deflectionoptical unit 13.

Further embodiments of deflection optical units that can be used insteadof the deflection optical unit 13 according to FIG. 13 in a systemincluding N projection exposure apparatises 1 are described below withreference to FIGS. 14 to 19. Component parts and functions that havealready been explained above with reference to FIGS. 1 to 13, and inparticular with reference to FIG. 13, bear the same reference signs andwill not be discussed in detail again.

A deflection optical unit 35 according to FIG. 14 has a total of fourmirrors D1, D2, D3, D4 in the beam path of the illumination light 3. Themirror D1 is embodied as a convex cylindrical mirror. The mirrors D2 toD4 are embodied as concave cylindrical mirrors.

More precise optical data can be gathered from the table below. In thiscase, the first column denotes the radius of curvature of the respectivemirror D1 to D4 and the second column denotes the distance between therespective mirror D1 to D3 and the respectively succeeding mirror D2 toD4. The distance relates to that distance which is covered by a centralray within the EUV individual output beam 9 _(i) between thecorresponding reflections. The unit used in this table and thesubsequent tables is in each case mm, unless described otherwise. TheEUV individual output beam 9 _(i) in this case is incident in thedeflection optical unit 13 with a semidiameter d_(in) 2 of 10 mm.

Radius of curvature Distance to the next mirror D1 2922.955800136.689360 D2 −49802.074797 244.501473 D3 −13652.672229 342.941568 D4−22802.433560

Table regarding FIG. 14

The deflection optical unit 35 according to FIG. 14 expands the x/yaspect ratio by a factor of 3.

FIG. 15 shows a further embodiment of a deflection optical unit 36likewise including four mirrors D1 to D4. The mirror D1 is a convexcylindrical mirror. The mirror D2 is a plane mirror. The mirrors D3 andD4 are two cylindrical mirrors having an identical radius of curvature.

More precise data can be gathered from the following table, whichcorresponds to the table regarding FIG. 14 in terms of layout.

Radius of curvature Distance to the next mirror D1 5080.620899130.543311 D2 0.000000 187.140820 D3 −18949.299940 226.054877 D4−18949.299940

Table regarding FIG. 15

The deflection optical unit 36 according to FIG. 15 expands the x/yaspect ratio of the EUV individual output beam 9 by a factor of 2.

FIG. 16 shows a further embodiment of a deflection optical unit 37including five mirrors D1 to D5. The first mirror D1 is a convexcylindrical mirror. The second mirror D2 is a plane mirror. The furthermirrors D3 to D5 are three concave cylindrical mirrors.

More precise data can be gathered from the following table, whichcorresponds to the tables regarding FIGS. 14 and 15 in terms of layout.

Radius of curvature Distance to the next mirror D1 3711.660251172.323866 D2 0.000000 352.407636 D3 −27795.782391 591.719804 D4−41999.478002 717.778100 D5 −101011.739006

Table regarding FIG. 16

The deflection optical unit 37 according to FIG. 16 expands the x/yaspect ratio of the EUV individual output beam 9 by a factor of 5.

A further embodiment of the deflection optical unit 37 differs from theembodiment according to FIG. 16 only in the radii of curvature and themirror distances, which are indicated in the following table:

Radius of curvature Distance to the next mirror D1 4283.491081169.288384 D2 0.000000 318.152124 D3 −26270.138665 486.408438 D4−41425.305704 572.928893 D5 −91162.344644

Table “Alternative design regarding FIG. 16”

In contrast to the first embodiment according to FIG. 16, thisalternative design has an expansion factor of 4 for the x/y aspectratio.

Yet another embodiment of the deflection optical unit 37 differs fromthe embodiment according to FIG. 16 in the radii of curvature and themirror distances, which are indicated in the following table:

Radius of curvature Distance to the next mirror D1 5645.378471164.790501 D2 0.000000 269.757678 D3 −28771.210382 361.997270 D4−55107.732703 424.013033 D5 −55107.732703

Table “Further alternative design” regarding FIG. 16

In contrast to the embodiment described above, this further alternativedesign has an expansion factor of 3 for the x/y-aspect ratio. The radiiof curvature of the last two mirrors D4 and D5 are identical.

FIG. 17 shows a further embodiment of a deflection optical unit 38including six mirrors D1 to D6. The first mirror D1 is a convexcylindrical mirror. The next two deflection mirrors D2, D3 are in eachcase concave cylindrical mirrors having an identical radius ofcurvature. The next deflection mirror D4 is a plane mirror. The last twodeflection mirrors D5, D6 of the deflection optical unit 38 are onceagain concave cylindrical mirrors having an identical radius ofcurvature.

More precise data can be gathered from the following table, whichcorresponds to the table regarding FIG. 16 in terms of layout.

Radius of curvature Distance to the next mirror D1 7402.070457197.715713 D2 −123031.042588 332.795789 D3 −123031.042588 459.491141 D40.000000 608.342998 D5 −87249.129389 857.423893 D6 −87249.129389

Table regarding FIG. 17

The deflection optical unit 38 has an expansion factor of 5 for the x/yaspect ratio.

FIG. 18 shows a further embodiment of a deflection optical unit 39including six mirrors D1 to D6. The first mirror D1 of the deflectionoptical unit 39 is a convex cylindrical mirror. The downstream seconddeflection mirror D2 is a plane mirror. The downstream deflectionmirrors D3 to D6 are in each case concave cylindrical mirrors. The radiiof curvature of the mirrors D3 and D4, on the one hand, and of themirrors D5 and D6, on the other hand, are identical.

More precise data can be gathered from the following table, whichcorresponds to the table regarding FIG. 17 in terms of layout.

Radius of curvature Distance to the next mirror D1 7950.882348196.142128 D2 0.000000 322.719989 D3 −207459.983757 451.327919 D4−207459.983757 627.317787 D5 −90430.481262 839.555523 D6 −90430.481262

Table regarding FIG. 18

The deflection optical unit 39 has an expansion factor of 5 for the x/yaspect ratio.

In an alternative design regarding FIG. 18, the mirror sequenceconvex/plane/concave/concave/concave/concave is exactly as in theabove-described embodiment of the deflection optical unit 39. Thisalternative design regarding FIG. 18 differs in the specific radii ofcurvature and mirror distances, as illustrated by the following table:

Radius of curvature Distance to the next mirror D1  10293.907897 S192.462359 D2    0.000000 S 285.944981 D3 −101659.408806 S 360.860262 D4−101659.408806 S 451.967976 D5 −101659.408806 S 517.093086 D6−101659.408806  

Table “Alternative design regarding FIG. 18”

This alternative design regarding FIG. 18 has an expansion factor of 4for the x/y aspect ratio of the EUV individual output beam 9.

FIG. 19 shows a further embodiment of a deflection optical unit 40including six mirrors D1 to D6. The first deflection mirror D1 of thedeflection optical unit 40 is a convex cylindrical mirror. The twodownstream deflection mirrors D2 and D3 are plane mirrors. Thedownstream deflection mirrors D4 to D6 of the deflection optical unit 40are concave cylindrical mirrors. The radii of curvature of the last twodeflection mirrors D5 and D6 are identical.

More precise data can be gathered from the following table, whichcorresponds to the table regarding FIG. 18 in terms of layout.

Radius of curvature Distance to the next mirror D1 8304.649871195.440359 D2 0.000000 314.991402 D3 0.000000 435.995630 D4−237176.552267 622.135962 D5 −85355.457233 852.531832 D6 −85355.457233

Table regarding FIG. 19

The deflection optical unit 40 has an expansion factor of 5 for the x/yaspect ratio.

In a further variant (not illustrated) the deflection optical unit has atotal of eight mirrors D1 to D8. The two leading deflection mirrors D1and D2 in the beam path of the EUV individual output beam 9 are concavecylindrical mirrors. The four downstream deflection mirrors D3 to D6 areconvex cylindrical mirrors. The last two deflection mirrors D7 and D8 ofthis deflection optical unit are once again concave cylindrical mirrors.

These mirrors D1 to D8 are connected to actuators 34 in a mannercomparable with the mirror D1 in FIG. 13, via which actuators a distancebetween adjacent mirrors D1 to D8 can be predefined.

The following table shows the design of this deflection optical unitincluding the eight mirrors D1 to D8, wherein the mirror distances fordifferent semidiameters d_(out)/2 of the emergent EUV individual outputbeam 9 _(i) are also indicated besides the radii of curvature. In thiscase, the EUV individual output beam is incident in the deflectionoptical unit including eight mirrors D1 to D8 with a semidiameterd_(in)/2 of 10 mm, such that expansion factors for the x/y aspect ratioof the deflected EUV individual output beam 9 _(i) of 4.0, of 4.5 and of5.0 are realized depending on the distance values indicated.

Distances [mm] Radius of curvature 40 mm for 45 mm semi- 50 mm [mm]semidiameter diameter semidiameter D1 −24933.160828 233.314949313.511608 355.515662 D2 −96792.387128 261.446908 184.453510 159.189884D3 13933.786194 120.747224 278.984993 124.048048 D4 7248.275614150.818354 311.248621 385.643707 D5 29532.874950 204.373669 219.654058296.180993 D6 100989.002210 872.703663 698.841397 665.602749 D7−87933.616578 1176.395997 1462.002885 1318.044212 D8 −79447.352117

In a further embodiment (likewise not illustrated) of the deflectionoptical unit, four mirrors D1 to D4 are present. The first mirror D1 andthe third mirror D3 in the beam path of the EUV individual output beam 9_(i) are embodied as convex cylindrical mirrors and the two furthermirrors D2 and D4 are embodied as concave cylindrical mirrors. Thefollowing table also indicates, besides the radii of curvature, distancevalues which are calculated for an input semidiameter d_(in)/2 of theEUV individual output beam 9 _(i) of 10 mm, that is to say which lead toexpansion factors upon passage through this deflection group includingthe four mirrors D1 to D4 for the x/y aspect ratio of 1.5, (semidiameterd_(out)/2 15 mm), of 1.75 (semidiameter d_(out)/2 17.5 mm) and of 2.0(semidiameter d_(out)/2 20 mm).

Distances [mm] Radius of curvature 15 mm for 17.5 mm 20 mm [mm]semidiameter semidiameter semidiameter D1 112692.464497 1718.2266306884.616863 7163.537958 D2 −488601.898900 250.044362 205.4330743185.838011 D3 112362.082498 1439.444519 263.976778 175.458248 D4−86905.078626

The deflection optical unit 13 can be designed in such a way thatparallel incident light leaves the deflection optical unit againparallel. The deviation of the directions of rays of the EUV individualoutput beam 9 _(i) that entered the deflection optical unit 13 withparallel incidence, after leaving the deflection optical unit, can beless than 10 mrad, in particular less than 1 mrad and in particular lessthan 100 μrad.

The mirrors Di of the deflection optical unit 13 can also be embodiedwithout refractive power, that is to say in plane fashion. This ispossible, in particular, if the x/y aspect ratio of an EUV collectiveoutput beam 7 has an aspect ratio of N:1, wherein N is a number of theprojection exposure apparatuses 1 to be supplied by the light source 2.The aspect ratio can also be multiplied by a desired setpoint aspectratio.

A deflection optical unit 13 composed of mirrors Di without refractivepower can consist of three to ten mirrors, in particular of four toeight mirrors, in particular of four or five mirrors.

The light source 2 can emit linearly polarized light; the polarizationdirection, that is to say the direction of the electric field strengthvector, of the illumination light 3 upon impinging on a mirror of thedeflection optical unit 13 can be perpendicular to the incidence plane.A deflection optical unit 13 composed of mirrors Di without refractivepower can consist of fewer than three mirrors, in particular of onemirror.

In the beam guiding optical unit 10, a focusing assembly 41 is disposeddownstream of the respective deflection optical unit in the beam path ofthe respective EUV individual output beam 9, the focusing assembly alsobeing designated as input coupling optical unit.

FIG. 20 schematically shows the function of the input coupling opticalunit 41 for one of the EUV individual output beams 9 _(i). The focusingassembly 41 transfers the respective EUV individual output beam 9 _(i)into an intermediate focus 42 of the beam guiding optical unit 10. Theintermediate focus 42 is arranged at the location of a through opening43 for the illumination light 3. The through opening 43 can be embodiedin a building ceiling of a building in which the system including theprojection exposure apparatuses 1 is accommodated. The building ceilingruns in an intermediate focal plane 44 of the beam guiding optical unit10, which is also illustrated in FIG. 1.

The focusing assembly 41 has an effective deflection angle for a centralchief ray CR of approximately 10°.

In another configuration, the focusing assembly 41 has an effectivedeflection angle for a central chief ray CR, wherein the effectivedeflection angle is between δ/2 and δ, and δ is the angle at theintermediate focus 42 between a central chief ray and a marginal ray.The sine of δ is also referred to as the numerical aperture (NA) of theradiation 3 at the intermediate focus 42.

FIG. 21 illustrates the focusing effect of an alternative focusingassembly 45 that can be used instead of the focusing assembly 41according to FIG. 20. In contrast to the focusing assembly 41, thefocusing assembly 45 deflects all individual rays of the incident EUVindividual output beam 9 _(i) in the xz-incidence plane in the samedeflection direction, namely toward negative y-values. The smallestdeflection angle of the focused individual ray 46 of the EUV individualoutput beam 9 _(i) that is illustrated on the far left in FIG. 21 isdesignated by α in FIG. 21 and is 5° or less.

The focusing assembly 45 has an effective deflection angle for thecentral chief ray CR of approximately 20°.

In another configuration, the focusing assembly 45 has an effectivedeflection angle for a central chief ray CR, wherein the effectivedeflection angle is between δ/2 and δ, and δ is the angle at theintermediate focus 42 between a central chief ray and a marginal ray.

Embodiment variants for focusing assemblies that can be used for thefocusing assemblies 41 or 45 are explained below with reference to FIGS.22 to 25.

FIGS. 22 to 25 in each case illustrate meridional sections through themirror reflection surfaces involved. Used reflection portions of themirror surfaces are highlighted by thicker lines. In order to elucidatethe surface design ellipsoid-hyperboloid/paraboloid, for the respectivemirror shape characteristic parent surface cuts are likewise depicted bythinner lines.

A focusing assembly 46 according to FIG. 22 has two mirrors disposeddownstream in the beam path of the respective EUV individual output beam9 _(i), namely a leading ellipsoidal mirror 47 and a downstreamhyperboloidal mirror 48.

An effective deflection angle for the central chief ray CR of the EUVindividual output beam 9 _(i) is approximately 50° in the case of thefocusing assembly 46. The deflection angles for the central chief ray CRupon reflection at the two mirrors 47 and 48 are added in the case ofthe focusing assembly 46.

The mirrors 47 and 48 are embodied as concave mirrors. The focusingassembly 46 is embodied in the manner of a type I Wolter collector.Information concerning the different types of Wolter collectors can befound in: H. Wolter, Spiegelsysteme streifenden Einfalls als abbildendeOptiken für Röntgenstrahlen [Grazing incidence mirror systems as imagingoptical units for X-rays], Annalen der Physik, volume 10, pages 94 to114, 1952.

In an alternative configuration, an effective deflection angle for thecentral chief ray CR of the EUV output beam 9 _(i) in the case of thefocusing assembly 46 is less than 40°, in particular less than 30°, inparticular less than 15°, and in particular less than 10°.

In an alternative configuration, an effective deflection angle for thecentral chief ray CR of the EUV output beam 9 _(i) in the case of thefocusing assembly 46 is less than double the angle between the centralchief ray CR and a marginal ray at the intermediate focus 42.

A focusing assembly 49 according to FIG. 23 likewise includes twomirrors, namely a leading ellipsoidal mirror 50 and a downstreamhyperboloidal mirror 51.

The mirror 50 is concave and the mirror 51 is convex.

The deflection angles for the central chief ray CR upon reflection atthe mirrors 50 and 51 are subtracted in the case of the focusingassembly 49.

An effective deflection angle for the chief ray CR is approximately 30°in the case of the focusing assembly 49.

The focusing assembly 49 is embodied in the manner of a type II Woltercollector.

In an alternative configuration, the focusing assembly 49 has aneffective deflection angle for the chief ray CR of a maximum of 20°, inparticular of a maximum of 15°, and in particular of a maximum of 10°.

In one configuration of the focusing assembly 49, the effectivedeflection angle for the chief ray CR is less than double the anglebetween the chief ray CR and a marginal ray at the intermediate focus42.

A focusing assembly 52 according to FIG. 24 likewise has two mirrorsdisposed downstream of one another in the beam path of the EUVindividual output beam 9 _(i), namely a leading paraboloidal mirror 53and a downstream ellipsoidal mirror 54.

The mirror 53 is convex and the mirror 54 is concave.

The deflection angles for the central chief ray CR upon reflection atthe mirrors 53 and 54 are subtracted in the case of the focusingassembly 52.

An effective deflection angle for the chief ray CR is approximately 50°in the case of the focusing assembly 52.

The focusing assembly 52 is embodied in the manner of a type III Woltercollector.

FIG. 25 shows a further embodiment of a focusing assembly 52, which islikewise embodied in the manner of a type III Wolter collector.Component parts and functions that have already been explained abovewith reference to the focusing assemblies according to FIGS. 21 to 24,and in particular with reference to the focusing assembly according toFIG. 24, bear the same reference signs and will not be discussed indetail again.

An output divergence of the EUV individual output beam 9 _(i) ispredefined by a numerical aperture NA of the EUV individual output beam9 _(i) at the intermediate focus 42. Depending on the numerical apertureNA, the following can be specified approximately for a transmission T ofthe focusing assembly according to FIG. 25:

T=1−0.9NA

In this case, the numerical aperture NA is defined as the sine of theangle between a chief ray and a marginal ray at the intermediate focus42. An equivalent definition states that the NA is the sine of half thebeam divergence angle.

A major semiaxis of an ellipsoid that describes the reflection surfaceof the ellipsoidal mirror 54 has the length a. A structural space 2 afor the focusing assembly 55 has a typical dimension of 2 a.

The typical structural space dimension 2 a is approximately fifty timesa beam diameter d of the EUV individual output beam 9 _(i) uponincidence in the focusing assembly 55. This ratio is at most weaklydependent on the numerical aperture NA at the intermediate focus 42.

A typical dimension of the reflection surfaces of the ellipsoidal mirror54 is likewise a. Given a typical extent of the reflection surface ofthe ellipsoidal mirror 54 of 1.4 m, a diameter of approximately 60 mmfollows for the beam diameter d.

The ellipsoidal mirror 54 has a short semiaxis b. The short semiaxis bis perpendicular to the plane of the drawing in FIG. 25. For the ratioof the semiaxes b/a it holds true that:

b/a˜0.8NA

In this case, NA is the numerical aperture at the intermediate focus 42.

The paraboloidal mirror 53 has a focal length f. For the ratio of thelong semiaxis a of the ellipsoidal mirror 54 and the focal length f ofthe paraboloidal mirror it holds true that:

a/f>50

During the production of a micro- or nanostructured component via theprojection exposure apparatus 1, firstly the reticle 12 and the wafer 24are provided. Afterwards, a structure on the reticle 12 is projectedonto a light-sensitive layer of the wafer 24 with the aid of theprojection exposure apparatus 1. Via the development of thelight-sensitive layer, a micro- or nanostructure is produced on thewafer 24 and the micro- or nanostructured component is thus produced,for example a semiconductor component in the form of a memory chip.

Further aspects of the projection exposure apparatus 1, in particular ofthe beam shaping optical unit 6, are described below.

Generally, the beam shaping optical unit 6 serves to shape thecollective output beam 7, which is also referred to as transport beam,from the raw beam 4. The collective output beam 7 is split into theindividual output beams 9 _(i), which are guided to different scanners,by the output coupling optical unit 8.

The transport beam can readily be transported over large distances. Forthis purpose, it is advantageous that the transport beam has a verysmall divergence. This is advantageous since the distance between thebeam shaping optical unit 6 and the scanners, in particular theillumination optical units 15 of the scanners, need not necessarily beknown.

In order to be able to split the transport beam more easily along thescanners, it is advantageous if it does not have a Gaussian profile, asis usually the case for the raw beam 4, but rather a substantiallyhomogeneous intensity profile. This can be achieved, as described above,by the beam shaping optical unit 6, in particular via reflection atfreeform surfaces.

A collective output beam 7 having a homogenous intensity profile makesit easier to split the collective output beam 7 uniformly into thedifferent individual output beams 9 _(i). It has been recognizedaccording to the disclosure, however, that the homogeneity property isnot absolutely necessary to achieve a dose stability of the individualscanners. Furthermore, it has been recognized that the collective outputbeam 7 need not necessarily have a rectangular intensity profile.

In accordance with one variant, the beam shaping optical unit 6 includesmirrors whose reflection surfaces are not embodied as freeform surfaces.It is possible, in particular, for the beam shaping optical unit 6 to beembodied in such a way that it exclusively includes mirrors whosereflection surfaces are not embodied as freeform surfaces.

The output coupling optical unit 8 and the deflection optical unit 13include in particular exclusively mirrors on which the illuminationradiation 3 impinges with grazing incidence. The deflection of theillumination radiation 3 by the deflection angle desired overall takesplace in particular with the aid of a plurality of reflections. Thetotal number of reflections in the output coupling optical unit 8 andthe deflection optical unit 13 is in particular at least 2, inparticular at least 3, in particular at least 4.

The beam shaping optical unit 6 is arranged between the radiation source2 and the output coupling optical unit 8, that is to say the opticalcomponent via which the collective output beam 7 is split intoindividual output beams 9 _(i).

The beam shaping optical unit 6 is embodied in particular in such a waythat the raw beam 4 is magnified in at least one direction perpendicularto the direction of propagation.

The beam shaping optical unit 6 is embodied in particular in such a waythat the cross section of the raw beam 4 is magnified in at least onedirection, in particular in two directions running obliquely, inparticular perpendicularly, with respect to one another. Themagnification scale is preferably in the range of between 1:4 and 1:50,in particular at least 1:6, in particular at least 1:8, in particular atleast 1:10.

At the input of the beam shaping optical unit 6, the raw beam 4 has inparticular a cross section with a diameter in the range of 1 mm to 10mm. At the output of the beam shaping optical unit 6, the collectiveoutput beam 7 has in particular a diameter in the range of 15 mm to 300mm, in particular of at least 30 mm, in particular at least 50 mm.

At the input of the beam shaping optical unit 6, the raw beam 4 has inparticular a divergence in the range of 25 μrad to 100 μrad. At theoutput of the beam shaping optical unit 6, the divergence of thecollective output beam 7 is in particular less than 10 μrad.

The beam shaping optical unit 6 is in particular telecentric. Itincludes at least two optically effective surfaces. The latter arepreferably operated with grazing incidence.

Preferably, the raw beam 4 is magnified in two directions that areoblique, in particular perpendicular, relative to one another. In thiscase, the beam shaping optical unit 6 includes at least two groupshaving in each case at least two optically effective surfaces, that isto say in particular at least four optically effective surfaces. Thebeam shaping optical unit 6 includes in particular the mirror groups 27,28. The mirror groups 27, 28 include in particular in each case twomirrors 27 _(i), 28 _(i).

The beam shaping optical unit 6 includes in particular at least one beamshaping mirror group 27, 28 having in each case at least two mirrors 27_(i), 28 _(i). The mirrors 27 _(i), 28 _(i) can have in each case asurface profile which is constant along a local coordinate and has aspherical course along a coordinate orthogonal thereto. This leads to amagnification of the raw beam 4 in just a single direction. It ispossible to use two mirror groups 27, 28 of this type in order tomagnify the raw beam 4 in two different directions, in particular twoorthogonal directions.

The mirrors 27 _(i), 28 _(i) can also have a spherical course having aradius R₁ of curvature along a first local coordinate and a sphericalcourse having a radius R₂ of curvature along a coordinate orthogonalthereto. R₁ and R₂ can in this case be identical or different. Such avariant leads to a magnification of the raw beam 4 in two mutuallyperpendicular directions.

The mirrors 27 _(i), 28 _(i) can also have in each case a surfaceprofile corresponding to an ellipsoid. This also leads to amagnification in two directions.

Preferably, the beam shaping optical unit 6 is arranged and embodied insuch a way that the raw beam, in particular the cross section thereof,is magnified in relation to a direction running parallel to the ground,that is to say parallel to a horizontal direction. The beam shapingoptical unit 6 is embodied in particular in such a way that thecollective output beam 7 at the output of the beam shaping optical unit6 runs parallel to the ground.

Further aspects and variants of the beam shaping optical unit 6 aredescribed below in a brief summary.

As was described above, it is not absolutely necessary for the raw beam4 to be homogenized via the beam shaping optical unit 6. However, ahomogenization of the raw beam 4 may be advantageous. It may lead inparticular to a higher material lifetime. It may also simplify theproducibility, in particular of the output coupling optical unit 8.

Depending on which aspect is of primary importance, it may be expedientand provision may be made for the raw beam 4 to be homogenized just inone direction. In this regard, it has been recognized that ahomogenization of the raw beam 4 in one direction has a positive effecton the material lifetime, while a homogenization in a directionorthogonal thereto is advantageous for the producibility, in particularof the output coupling optical unit 8.

Since, as was described above, the beam shaping optical unit 6 has forthese two directions in each case separate groups 27, 28 of mirrors 27_(i), 28 _(i), in particular separate mirror pairs, for example one ofthe mirror pairs can be embodied as tori, and the other as freeformsurfaces. This leads to a cost saving.

Different variants of the homogenization of the raw beam 4 via the beamshaping optical unit 6 are illustrated schematically in FIGS. 26 to 28.FIG. 26 schematically illustrates the embodiment of a beam shapingoptical unit 6 via which the raw beam 4 is homogenized in two mutuallyperpendicular directions. This is clarified by a stepped course of anintensity profile 56 in a first direction and a stepped course of anintensity profile 57 in a second direction. The intensity profiles 56,57 relate to the intensity of the illumination radiation 3 in a crosssection of the collective output beam 7 perpendicular to the directionof propagation thereof.

FIG. 27 illustrates a variant of the beam shaping optical unit 6 inwhich the raw beam 4 is homogenized only in the second direction.Accordingly, the intensity profile 57 has a stepped course. Theintensity profile 56 has an inhomogeneous, in particular a non-stepped,in particular a Gaussian, course. In other words, a local increase inintensity occurs in a central region of the collective output beam 7,which runs in the vertical direction in FIG. 27.

FIG. 28 correspondingly illustrates a variant of the beam shapingoptical unit 6 in which, in comparison with the embodiment in accordancewith FIG. 27, the raw beam 4 is homogenized precisely in the otherdirection. In this embodiment, the intensity profile 56 in the firstdirection has a stepped course. The intensity profile 57 in the seconddirection is not homogeneous, in particular non-stepped, in particularGaussian. The intensity is increased in a horizontally running centralregion.

Intermediate steps are also possible. It is possible, in particular, topartially homogenize the raw beam 4 in one or both directions. It ispossible, in particular, to homogenize the raw beam 4 in one or bothdirections in such a way that the intensity of the illuminationradiation at different spatial coordinates in the direction differs ineach case only by a maximum of 25%. Intensity spikes, in particular, canbe avoided by a corresponding homogenization. This has an advantageouseffect in particular on the material lifetime.

The intensity profile 56 and/or the intensity profile 57 can have inparticular a form which is neither exactly Gaussian nor exactly stepped,but rather has a Gaussian and a stepped proportion. The intensityprofile 56 and/or the intensity profile 57 can be described inparticular as a sum of a Gaussian proportion and a stepped proportion.

An inhomogeneity of the collective output beam 7 in the second directioncan be compensated for by the fact that the regions of the collectiveoutput beam 7 which are coupled out into the different individual outputbeams 9 _(i) by the output coupling optical unit 8 are of differentsizes. The size of the regions makes it possible to predefine whatproportion with the illumination radiation 3 in the collective outputbeam 7 is guided to the individual scanners.

FIG. 29 illustrates an optical element for magnifying the cross sectionof a beam with illumination radiation 3. For magnifying the beam crosssection, a mirror 58 having a convex reflection surface is arranged inthe beam path of the illumination radiation 3. The mirror 58 is alsoreferred to as a diverging mirror.

The mirror 58 can have a substantially cylindrical reflection surface,that is to say can be convex in a first direction and plane in a seconddirection, running perpendicular to the first direction. It can also beconvex in both directions. In this case, the radii of curvature can beidentical or different. In principle, it is also possible to embody themirror 58 with adjustable radii of curvature, in particular radii ofcurvature that are adjustable by an actuator system. The selection ofthe radii of curvature of the mirror 58 relative to the first directionand the second direction perpendicular thereto makes it possible toinfluence the magnification of the cross section in the correspondingdirections in a targeted manner.

The mirror 58 can thus be used for the targeted magnification of thecross section of the beam or beam of rays with illumination radiation 3.

What is claimed is:
 1. A beam guiding optical unit, comprising: afocusing assembly configured to transfer an EUV individual output beaminto an intermediate focus of the beam guiding optical unit, wherein thebeam guiding unit is an EUV lithography beam guiding unit.
 2. The beamguiding optical unit of claim 2, comprising: an ellipsoidal mirror; andat least one mirror selected from the group consisting of a paraboloidalmirror and a hyperboloidal mirror.
 3. A deflection optical unit,comprising: a plurality of deflection mirrors on which EUV radiationimpinges in a common deflection incidence plane with grazing incidenceduring use of the deflection optical unit, wherein: the plurality ofdeflection mirrors comprises at least four deflection mirrors whichjointly have a deflection effect in the common deflection incidenceplane of more than 70°; and at least one of the deflection mirrors isselected from the group consisting of a convex cylindrical mirror and aconcave cylindrical mirror.
 4. The deflection optical unit of claim 3,wherein at least one of the deflection mirrors is displaceable in adriven fashion.
 5. The deflection optical unit of claim 3, wherein atleast one of the deflection mirrors has a radius of curvature that isvariable in a driven fashion.
 6. A beam shaping optical unit,comprising: at least two groups of mirrors on which EUV radiationimpinges with grazing incidence during use of the beam shaping opticalunit, wherein each mirror group has a common group incidence plane, thegroup incidence planes of the mirror groups differ from one another, andthe beam shaping unit is an EUV lithography beam shaping unit.
 7. Thebeam shaping optical unit of claim 6, wherein: the beam shaping opticalunit comprises first, second and third groups of mirrors; all mirrors ofthe first group of mirrors are in a beam path downstream of a firstmirror of the second group of mirrors; and all the mirrors of the firstgroup of mirrors are upstream of a last mirror of the third group ofmirrors.
 8. The beam shaping optical unit of claim 6, wherein the anglesof incidence of the EUV radiation on all mirrors of one of the mirrorgroups are of identical magnitude.
 9. The beam shaping optical unit ofclaim 6, wherein the angles of incidence of the EUV radiation on atleast two mirrors of one of the mirror groups differ.
 10. The beamshaping optical unit of claim 9, wherein, projected onto the commongroup incidence plane of the group of mirrors with different angles ofincidence, a generated EUV collective output beam runs in the samedirection as an EUV raw beam that is incident in the beam shapingoptical unit.
 11. An illumination system, comprising: a beam shapingoptical unit configured to generate an EUV collective output beam froman EUV raw beam of a synchrotron-radiation-based light source; an outputcoupling optical unit configured to generate a plurality of EUVindividual output beams from the EUV collective output beam; for eachEUV individual output beam, a beam guiding optical unit configured toguide the EUV individual output beam toward an object field in which alithography mask is arrangable, wherein the illumination system is anEUV projection lithography illumination system.
 12. The illuminationsystem of claim 11, wherein: the beam shaping optical unit is configuredto generate the EUV collective output beam with an aspect ratiocontribution of 1:√{square root over (N)}; and at least one memberselected from the group consisting of the output coupling optical unitand the beam guiding optical unit is configured to subsequently generatea number N of the EUV individual output beams with an aspect ratiocontribution of in each case 1:1.
 13. The illumination system of claim11, further comprising an EUV light source.
 14. An apparatus,comprising: an illumination system according to claim 11; and aprojection optical unit configured to image the object field into animage field, wherein the apparatus is an EUV lithography projectionexposure apparatus.
 15. A method of using an EUV lithography projectionexposure apparatus comprising an illumination system and a projectionoptical unit, the method comprising: using the illumination system toilluminate at least a portion of a reticle comprising a structure; usingthe projection optical unit to project the illuminated structure of thereticle onto a light-sensitive layer of a wafer, wherein theillumination system is an illumination system according to claim
 11. 16.The beam guiding optical unit of claim 1, wherein the focusing assemblycomprises: a concave ellipsoidal mirror; and at least one mirrorselected from the group consisting of a convex paraboloidal mirror, aconcave hyperboloidal mirror, and a convex hyperboloidal mirror.
 17. Thebeam guiding optical of claim 1, further an illumination optical unitarranged downstream of the focusing assembly, wherein the illuminationoptical unit comprises a field facet mirror and a pupil facet mirror.18. The beam guiding optical unit of claim 1, wherein the focusingassembly has an effective deflection angle for a central chief ray ofthe EUV output beam, and the effective deflection angle is less thandouble an angle between a central chief ray and a marginal ray at theintermediate focus of the beam guiding optical unit.
 19. The beamguiding optical unit of claim 1, wherein the focusing assemblycomprises: an ellipsoidal mirror with a major semiaxis α of theellipsoidal mirror; and a paraboloidal mirror with a focal length f ofthe paraboloidal mirror, wherein a ratio α to f is greater than
 50. 20.The beam guiding optical unit of claim 2, wherein the focusing assemblycomprises a member selected from the group consisting of a Wolter mirrorgroup of type I, a Wolter mirror group of type II, and a Wolter mirrorgroup of type III.
 21. The beam guiding optical unit of claim 2, whereinmirrors of the focusing assembly are arranged sequentially in a beampath of the EUV individual output beam.
 22. The beam guiding opticalunit of claim 2, wherein a structural space of the focusing assemblyalong a beam path of the EUV individual output beam is approximatelydouble a magnitude of a major semiaxis of an ellipsoidal mirror of thefocusing assembly.
 23. The beam guiding optical unit of claim 2, whereina structural space of the focusing assembly along a beam path of the EUVindividual output beam is approximately fifty times a magnitude of adiameter of the EUV individual output beam upon entering the focusingassembly.